The EGR has its vacuum source and the brake boster has its vacuum source not the same,I can’t see where this could go. I don’t think the Dealer would deliver you your car with the boster inoperative,how could they test drive it? Certainly if they released your car to you with the boster inop you would have been told,this is dangerous.
You are relating your poor brake system performance to both “air in the lines” and no vacuum to the boster,not making sense.